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View Full Version : Underdsrive pulley on PS on Daily Driver- bad idea?


burntkat
July 28th, 2017, 08:19
Folks-

I am curious if anyone has experience using an underdrive (aka "smaller outside diameter, so it spins the pump faster") pulley on a daily driver.

It's obvious of course that this gives superior performance at idle speed as the pump is spinning faster. However, it will also be spinning faster at speed- shift points being what they are, that can often be 4K rpm going down the interstate. I'm concerned about the fluid aerating as the pump cavitates at higher speeds.

Is this a realistic concern? I know the rockcrawling guys often use these, but those same rigs are often trailer queens.

As my hydraulic pump runs both my steering and braking, I could use higher performance. At the same time, I don't need issues with fluid aeration.

cal
July 28th, 2017, 08:31
king of the hammers cars use these and sit at very high rpms for very long times without problem.

may require larger fluid reservoir and will require a good cooler.

VAhasnoWAVES
July 28th, 2017, 08:59
the pump has a maximum output before it goes into bypass.

i run a PSE high flow pump, overdrive pulley, and hydro assist. being geared 5.13 with 35s, i see some high RPMs above 60mph. zero issues. good fluid and a cooler make a difference. i run swepco 715 (per PSE's recommendation for their pump).

jk_surgeonfish
July 28th, 2017, 10:40
What cooler is everyone running?

cal
July 28th, 2017, 11:11
https://www.summitracing.com/parts/ear-41300erl/overview/

burntkat
July 28th, 2017, 11:33
Thanks, gents. That's the kind of info I was looking for. Ill order the pulley today.

I don't suppose anyone knows a good pulley for a SBC 350 that doesn't have a solid body? I don't have much clearance between the radiator and the pulley, so I need the ability to get the pump in/out with the pulley attached.

cal
July 28th, 2017, 11:34
http://www.pscmotorsports.com/4-5-serpentine-6-rib-pulley-tc-series-pump.html

RWKHausSupply
July 28th, 2017, 12:33
I have a pulley I let you have for cheap...

Oh its that pully Cal linked to up there.
25$ and flat rate USPS = 35$

XJEEPER
July 28th, 2017, 12:37
http://www.pscmotorsports.com/4-5-serpentine-6-rib-pulley-tc-series-pump.html

I'm running this pulley on my XJ, which is freeway driven to and from the trails (3-5hrs each way) with zero issues. Large cooler and more fluid capacity are your friends when trying to keep the PS system happy.

jk_surgeonfish
July 28th, 2017, 12:41
https://www.summitracing.com/parts/ear-41300erl/overview/

Nice. Now... where is a good spot to mount this?

XJEEPER
July 28th, 2017, 12:52
http://www.pscmotorsports.com/4-5-serpentine-6-rib-pulley-tc-series-pump.html

I'm running this pulley on my XJ, which is freeway driven to and from the trails (3-5hrs each way) with zero issues. Large cooler and more fluid capacity are your friends when trying to keep the PS system happy.

burntkat
July 28th, 2017, 13:53
http://www.pscmotorsports.com/4-5-serpentine-6-rib-pulley-tc-series-pump.html

What about it? It won't work in my application, as I use a P-series pump

burntkat
July 28th, 2017, 13:54
Large cooler and more fluid capacity are your friends when trying to keep the PS system happy.

Indeed.

Also works very well for the tranny.

burntkat
July 28th, 2017, 14:23
A bit more information on my build-

At present this is in an S10- so it isn't XJ-specific- but power steering is, so I posted here (also, the S10 board I was on recently went dark).

It's a Smallblock Chevy 350, Saginaw P-series pump, running the hydroboost and steering box from a 97 Astro. Please note that the reason I went to the Astro box is because I moved the front axle forward approx 3"- in this case, coupled with the fact the Astro box is RR, it gave me *perfect* steering angles- my bars are both parallel (or as darn close as I can tell) to the horizon. I'm also running a power steering cooler and a 1-quart spin-on hydraulic filter.

Why a 97 Astro, you ask? I was going hydroboost, and the 97 Astro is HB right from the start, and also happens to have the highest-rated COTS-available P-series pump. I can get replacements for $50, not $250.

In all honesty, if I could run this setup in an XJ, I would in a heartbeat. The only issue there is it's a P-series pump, not the TC-series the XJ needs. I have not yet looked into the mounting differences- if anyone has input there please let me know.

So, why the need for a PS Pulley with spokes or holes in the face? Because I've got about 2" between the pulley and the radiator. I installed a 350 in the truck, where a 4.3 used to live. I'm tired of having to pull the radiator to do any PS work (which I'll grant, doesn't happen often- but it's a royal PITA when it does).

burntkat
July 28th, 2017, 14:50
Nice. Now... where is a good spot to mount this?

I've mounted all of my PS coolers in front of the radiator. It *must* be in a high-airflow, ambient-air-temp location to work properly, or have cool air forced to it via ducting or fans.

I'm just running a cheap bent-tube affair, it works quite well. I don't have numbers on it.

For tranny, I use a cooler like the one specified earlier in this thread- but that's a more critical system, and has higher loading.